(19)
(11) EP 0 456 182 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
11.03.1992 Bulletin 1992/11

(43) Date of publication A2:
13.11.1991 Bulletin 1991/46

(21) Application number: 91107394.8

(22) Date of filing: 07.05.1991
(51) International Patent Classification (IPC)5: H01L 39/24, C04B 35/50
(84) Designated Contracting States:
DE FR GB

(30) Priority: 08.05.1990 JP 118363/90

(71) Applicants:
  • INTERNATIONAL SUPERCONDUCTIVITY TECHNOLOGY CENTER
    Tokyo (JP)
  • TOYOTA JIDOSHA KABUSHIKI KAISHA
    Aichi-ken (JP)
  • Kawasaki Jukogyo Kabushiki Kaisha
    Kobe-shi Hyogo 650-91 (JP)
  • NGK INSULATORS, LTD.
    Nagoya-shi, Aichi 467 (JP)

(72) Inventors:
  • Sakai, Takenobu
    Tougou-cho, Aichi-gun, Aichi-ken (JP)
  • Nishio, Koji
    Nada-ku, Kobe (JP)
  • Ogawa, Naoyuki
    Sasame-cho, Anjou 446 (JP)
  • Hirabayashi, Izumi, c/o Superconductivity Res. Lab
    2-chome, Atsuta-ku, Nagoya-shi, Aichi (JP)
  • Tanaka, Shoji, c/o Superconductivity Res. Lab
    1-chome, Koto-ku, Tokyo, 135 (JP)

(74) Representative: Bühling, Gerhard, Dipl.-Chem. et al
Patentanwaltsbüro Tiedtke-Bühling-Kinne & Partner Bavariaring 4
80336 München
80336 München (DE)


(56) References cited: : 
   
       


    (54) Oxide superconductor and process for producing the same


    (57) Disclosed are an oxide superconductor, and an optimum process for producing the same. The oxide superconductor comprises a base material phase including an oxide superconducting material, the oxide superconducting material including barium (Ba) at least and being free from grain boundaries, and precipitation phases contained in an amount of 1 to 50% by volume in the base material phase and dotted therein in a manner like islands, the precipitation phases being oxides of a metal selected from the group consisting of silicon (Si), aluminum (Al), zirconium (Zr), magnesium (Mg), titanium (Ti), strontium (Sr), tungsten (W), cobalt (Co) and vanadium (V), and being products of decomposition reaction of the base material phase. In the production process, the constituent materials are treated thermally at a partially melting temperature in order to give the above-described novel structure to the oxide superconductor. Thus, the precipitation phases are dotted in a manner like islands in a sea of the base material phase being free from the grain boundaries, and the precipitation phases work as the pinning centers. Therefore, the oxide superconductor exhibits a high "Jc" value.






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